1. Field of the Invention
This invention relates to agricultural earthworking methods and equipment. Applicants designate one with ordinary skill in the art to be a farmer, agricultural engineer, or a person having experience in the construction and operation of agricultural earthworking equipment.
2. Description of the Prior Art
Farmers have always had difficulty plowing a straight furrow. Surface undulations, rocks, clods, clumps of weeds, grass and roots, steering corrections, and other causes of lateral shifts, jumps, jerks, wiggles or waggles of the earthworking implements can not be accounted for with prior art equipment.
One prior art solution has been to attach a coulter or disc to the earthworking tools or implements to minimize sudden lateral shifts. The use of such coulters attached to drafted implements helped somewhat in obtaining "acceptably straight" furrows or plowing, for that technology. However, even the "acceptable" lateral deflections or wiggles permitted by the prior art caused problems.
Those skilled in the art will be aware of the small "wiggles" or "crooks" in furrows and beds plowed by even the most expert farmer using the best prior art equipment. The wiggles or crooks of the beds, when combined with lateral wiggles of the planters, frequently result in crops being sown off-centered on the beds, or even on the side of the beds in the furrows. Later, when the crops have sprouted, mechanical treatment for weeds, such as with sweeps, requires that the individual sweeps be run at a generous clearance from the bed centers to avoid damaging off-centered crop plants, and to allow for wiggles or lateral swings of the sweeps.
Early self-powered agricultural tractors mounted earthworking implements underslung below the tractor, forward of the tractor rear. Development of the art since those early devices has resulted in more powerful tractors, with earthworking implements hitched at the tractor rear. The rear hitch tends to lift the front wheels of the tractor off the ground during heavy drafting. Those skilled in the art will recall the counterweights commonly used at the tractor front to counteract this tendency.
Before this application was filed, a search was made in the U.S. Patent and Trademark Office. That search developed the following patents:
PLUM U.S. Pat. No. 1,608,666 PA1 ALTGELT U.S. Pat. No. 2,637,262 PA1 STEFFE U.S. Pat. No. 3,601,202 PA1 CAPEHART U.S. Pat. No. 3,840,076 PA1 QUANBECK U.S. Pat. No. 4,068,723
These patents are disclosed because such references, developed by an experienced searcher, might be considered relevant and pertinent to the examination of this application.